Abstract: :
Purpose: To develop alternatives to silicon oil and perflurocarbonliquids for repair of complex retinal detachments. We seek tocreate an artificial version of the formed, juvenile vitreoususing newly developed polymeric sol-gel systems. This wouldavoid issues related to patient positioning and known toxicityof current materials as well as provide better treatment ofinferior tears. By selecting such systems, we also can avoidexposure of the intra-ocular tissues to toxic monomers and thethermal energy present in exothermic in vivo polymerizationreactions. Unique to our system is the ability to induce swellingof the polymer after cross-linking (formation of the gel) andthus tamponade the retinal tear.Methods: In this proof-of-principleseries of experiments, we have utilized our sol-gel system [H.Aliyar,P.Hamilton, N.Ravi, Investigation On In-situ Endocapsular GelationOf Copolyacrylamides, ARVO 2002 B384], allowed cross-linkingin vivo, and induced swelling of the gel through normal hydrationin the vitreous cavity in human cadaver eyes. We performed apneumatic vitrectomy and then instilled the polymer into thevitreous cavity through a pars-plana approach. The eye was thenmaintained oriented upward (as if the patient were lying supine).After the gel had polymerized and swollen, the globes were examined.Results: We have successfully implemented the above protocolin cadavaric eyes. The hydrated gel was formed and noted tohave vitreous-like consistency. Gels of similar composition,formed in vitro, have an elastic modulus of 100-150 Pa and containmore than 98% water. In performing the procedure, we have developedexperience that will guide animal studies as well as trialsof other sol-gel systems.Conclusions: Spontaneously formingreversible sol-gel systems are a reasonable alternative to currentvitreous substitutes. By changing paradigm from a liquid orgas to a formed artificial vitreous that tamponades the retinaagainst the RPE, we may avoid the limitations of current substitutessuch as the need for face-down positioning, need for a secondsurgery to remove oil, glaucoma, and toxicity. Further workis needed to evaluate toxicity and the risk of complications.